Graduate Microbiology · The Prokaryotic Cell
Bacteria
The first cells, the most numerous cells, and the cells without which we — and the rest of the biosphere — would not exist.
About This Course
Bacteria invented life. For roughly two billion years before the first eukaryotic cell, the planet was theirs alone. Today they outnumber every other class of organism by orders of magnitude (an estimated 1030 bacterial cells on Earth, ~1014 in your body), drive every biogeochemical cycle, manufacture most of our antibiotics, cause many of our diseases, and live as the microbiome on which our metabolism quietly depends.
This course is the graduate-level companion to the prokaryote half of cell biology. We trace the field from Leeuwenhoek’s 1676 letters to the Royal Society describing “animalcules” through Pasteur, Koch, the rRNA revolution of Carl Woese, and into the modern era of antibiotic resistance and the microbiome. The eight modules cover bacterial architecture, the cell wall and the Gram stain, genetics and operons, the elegant rotary flagellum, biofilms and quorum sensing, antibiotics and the molecular machinery of resistance, and host–microbe biology.
Key Numbers
1030
Bacterial cells on Earth
~1 μm
Typical rod length
~20 min
E. coli generation time
~4 Mbp
E. coli genome size
~100 Hz
Flagellar rotation rate
1014
Bacteria in your body
Eight Modules
M0
Discovery & Tree of Life
Leeuwenhoek 1676, Pasteur, Koch’s postulates, Carl Woese 16S rRNA and the three domains. Bacteria vs Archaea vs Eukarya.
M1
Cell Architecture
Plasma membrane, cytoplasm, 70S ribosomes, nucleoid (Cairns 1963 autoradiograph), plasmids, capsule, fimbriae, sex pili.
M2
Cell Wall (Gram +/−)
Peptidoglycan biosynthesis (Lipid II, transglycosylation, transpeptidation), teichoic acids, LPS endotoxin, mycobacterial mycolic acids.
M3
Genetics & Operons
Circular chromosome, replication forks, RNA polymerase + sigma factors, lac and trp operons (Jacob & Monod 1961), two-component systems.
M4
Motility & Chemotaxis
The flagellar rotary motor (~30 nm proton turbine), run-and-tumble navigation, Berg-Purcell limit, CheA/Y/B/Z signalling cascade.
M5
Biofilms & Quorum Sensing
EPS matrix architecture, biofilm life cycle, AHL (Gram−) and AIP (Gram+) autoinducers, V. fischeri lux operon, V. cholerae virulence.
M6
Antibiotics & Resistance
β-lactams, aminoglycosides, macrolides, fluoroquinolones, glycopeptides. β-lactamases, efflux pumps, target modification, the AMR crisis.
M7
Microbiome & Pathogenesis
Gut microbiome composition (Bacteroidetes vs Firmicutes), dysbiosis, T3SS/T4SS injection systems, AB toxins (cholera, diphtheria), endotoxic shock.
Cross-Links
Virus,Molecular Biology,Biochemistry,Pharmacology,Origin of Life,Bioinformatics.